Generally, an optical fiber consists of an optically transparent, flexible fiber core coaxially covered by an outer cladding. The fiber core is formed of glass and the cladding is formed of a glass material having an index of refraction which provides propagation of successive reflections of light in the fiber core along the length of the fiber core. Surrounding the outer cladding of the fiber is a protective buffer of plastic or PVC. The fiber (core and cladding) and buffer together make up a fiber optic cable. Plural of such optical cables are often carried in parallel in a common outer jacket and compose what is known as an optical fiber bundle.
An example of a typical optical fiber cable is shown in FIG. 1a. The cable 15 is shown extending from an outer jacket 9. Other cables are not shown in the outer jacket, but it will be understood that such jackets typically carry a number of optical fiber cables. As shown in FIG. 1a, the optical fiber cable 15 shown consists of an optical fiber 47 which is a core surrounded by a cladding material. Surrounding the cladding of the fiber 47 is a buffer material 16 which protects the fiber within.
As used herein the term "fiber optics" implies both single optical fiber cables and optical fiber bundles unless otherwise stated.
Fiber optics have enjoyed wide spread use in electro-optical and opto-mechanical systems. Example applications are communication systems and sensor systems. Typically an optical fiber transfers subject lightwaves from a source (e.g. a transmitter) to a desired receiver (e.g. a light detector) which in turn transmits responsive electrical signals or the like. In order to perfect such transfers between fiber optics and electro-optic devices (transmitters, detectors, etc.) various connectors have been used to ensure proper alignment between the fibers and devices.
A common connector employs a first member for fixedly holding the receiver/transmitter device aligned behind an aperture in the first member, and a second member for fixedly holding the optical fiber of interest. The two members screw together or otherwise fit together to place the end of the optical fiber in the vicinity of the aperture of the first member and hence aligned with the device. However, once the two members are fitted together, it is difficult to determine whether the fiber end is sufficiently close to the device. This often results in the fiber being a good distance from the electro-optic device such that the light coupling between the fiber and device is not maximized. To improve on this coupling, fibers used with the prior art connectors are polished on the end, often forming lens structures, to improve the coupling of the light to the device. However, this step adds times and expense to the connection procedure.
Another disadvantage of prior art connectors concerns the space (surface area and volume) that a connector occupies on a circuit board. That is, many of the applications of fiber optics involve coupling the multiple fibers of a fiber bundle to respective electronic devices and attaching the employed fiber-to-device connectors to the circuit board. Each connector must be of a position and size such that the board can accomodate them in an arrangement that minimizes bending of fibers. If optical fibers are excessively bent, losses and transfer errors are introduced.